Here’s an interest pentode to consider for phono stages. It was used extensively in instrumentation up until 1980s. There are a few examples around and you can check the Brimar data sheet to see what I’m taking about.
Continue reading “6BS7 low noise pentode”Category: Pre-amplifier
VT-25/801a/10Y DHT Preamp with SiC filament bias
For quite some time now I wanted to share one of the variations of the famous VT-25/10Y pre-amplifier. As usual due to work, business travel and family duties, I’ve struggled to find the time to update the blog.
Continue reading “VT-25/801a/10Y DHT Preamp with SiC filament bias”6F12P a great Russian valve
The 6F12P is used (by many) in Europe (mainly) in RIAA circuit. You would wonder why? Well, it’s a great Russian frame-pentode which has high-mu and high-gm therefore driving larger currents at low distortion.
Bootstrapped CF (SLCF) PCB tests
Long time ago I used this SLCF circuit as an output buffer with excellent results. It sounds as clean as it can get in my opinion. Recently, I made up a PCB to hold this circuit with a varied of options:
ETF.18 DHT Preamps Lecture
ETF.18 has been an emotional journey. I moved house literarily when I got back from ETF so my life has been more than hectic over the past few weeks.
I promise I will do a write-up of this amazing experience. There’s a lot of people out there who would love to attend so is my duty to reflect and share as much as I can.
In the meantime, I wanted to share the lecture I gave at ETF on DHT preamps. It was a challenge on its own but went really well. This was my first ETF and without knowing the audience I had to guess the level of detail, entertainment and expectations of an unknown audience. I knew a fair bit of the ETF folks, but audience was big and wide.
I struggled to find the time to prepare this lecture I have to confess. Between moving house, house building works, my second daughter’s arrival , weekly work travel and everything else, I seemed not to find the time to get this done. Thank you Morgan Jones and Rod Coleman for proof-reading and making this an easier task.
I hope you enjoy it. There are some notes on the slides I put together for the people who didn’t attend ETF. Otherwise the slides aren’t of much use on their own.
I’m writing this blog entry whilst enjoying the lovely Bourbon that Pete Millett gave me on the way back. Thanks Pete!
ETF Lecture on DHT Preamps (with notes):
DHT-Preamps-ETF2018-final-notes
ETF Lecture on DHT Preamps (slides):
Tuning the system for ETF
This year I entered the shootout competition and will bring my DHT system to the European Triode Festival in France. It’s comprised of the ER801a stage plus the 01a (if extra gain is needed) and the 4P1L PSE output stage
I will have to swap out the amorphous OPT for the Monolith Magnetic ones as the speaker load is 5R.
It’s going to be interesting!
Ba DHT Preamp Build
Just in the last days before the arrival of our second child, I had a spot of luck and managed to get some free time to work on my DHT preamp experiments.
Originally I was put off by the hum pickup susceptibility of the Ba German DHT. However, I decided it was time to listen to the design I worked and experimented in my workshop time ago. I remember listening to this valve and was very pleased with its sound.
Continue reading “Ba DHT Preamp Build”DHT Audio Shootout @ London
Here’s the summary of the shootout day we had yesterday at my place with Tony Rees and Andy Evans
Test Music
For testing the pre-amps Andy suggested the following 2 tracks:
- Ravel Feria (Cleveland/Boulez)
- Janacek The Cunning Little Vixen Act 3 Scene 7 “A vixen’s running through the woods” Prague Theatre/Gregor
Andy Evans
The Ravel is orchestrated for a large orchestra and percussion, and listening was particularly for the timbre of strings, brass and woodwind and the clarity of the percussion. The Janacek is for several different voices and chorus, and listening was for the tone and character of the voices and how well they were differentiated from each other. In both cases the overall clarity, life and crispness was considered.
Although I wasn’t familiarised enough with these 2 tracks myself, I found them to be an excellent choice and a reflection of Andy’s musical experience and knowledge as musician.
Continue reading “DHT Audio Shootout @ London”6Э6П-ДР (6e6p-dr) preamp / driver
With a quick mod on one of my active preamps, I managed to implement very quickly the 6Э6П-ДР (6e6p-dr) driver in my system. Here is how the circuit looks like:
ELROG ER801-A Review
I’ve been listening for over a week the Elrog ER801a prototypes. I can say that I’m very please with them. Before I make any further impressions about their sound, let me start from the beginning.
I purchased last year from ELROG (now Deutsche Elektronenröhren Manufaktur GmbH.) a pair of these valves to be used on my VT25/10Y preamp. I do not own any 801a, but have a good stash of NOS VT25 and 10Y valves. I love this preamp, probably my favourite with the 01a.
Thomas Mayer offered me to send me a preliminary set of prototype valves in advance so I can submit them to the mercy of my tests. That sounded like really good fun and also I thought that the folks out there would be very keen to see the results.